The action of ocean waves on sandy beaches often leads to significant loss of shoreline due to beach erosion, as the waves repeatedly break onto the beach, causing sand to mix with the water and wash out to sea as the waves recede. Beach erosion is an issue of significant economic, esthetic, ecological, and practical concern, such that a considerable amount of effort and cost are expended each year in various attempts to protect and rebuild beaches.
Attempts to reduce or reverse beach erosion are generally directed to re-directing or blocking the energy of ocean waves before they reach the shoreline. One approach is to install an artificial breakwater, levee, or “groin” that blocks wave action and creates a region of low wave activity that is essentially an artificial harbor or cove. However, these structures are very large and heavy, expensive to build, and nearly impossible to remove or relocate as localized requirements evolve. Also, sand often tends to collect on one side of such a breakwater or levee, and be diminished on the other side, which may not be a desired effect.
Another approach is to submerge any of various types of barriers at or beyond the low tide level so as to partially block waves as they approach the shore and thereby reduce the energy with which the waves strike the beach. Some of these barriers include open tops or flow-through holes that encourage the sea water to pool long enough for any entrained sand to settle behind them and/or within their interiors. However, such barriers are also heavy, expensive to manufacture and install, and difficult to remove or relocate as needed.
Yet another approach is to deposit heavy chunks of concrete and/or other such materials, generally referred to as “riprap,” below the waterline, which also has the effect of reducing wave energy and encouraging entrained sand to settle. While somewhat less expensive to manufacture and install than other forms of underwater barrier, riprap is virtually impossible to remove or relocate. Also, riprap can tend to become buried over time as sand is deposited, thereby reducing and eliminating its effectiveness.
The most common approach to reducing beach erosion that is implemented above the waterline is the planting of shoreline-compatible grasses that tend to stabilize the sand and protect it from wind erosion, and from the onrush of wave-driven water near the high tide mark. Such grasses can further serve to filter the ocean water as it recedes, so as to strain out and retain any sand that is entrained therein. However, shoreline-compatible grasses can be expensive, difficult, and time-consuming to establish, and grasses are not a viable solution when a sand beach is desired for recreational and/or other purposes.
What is needed, therefore, is an apparatus for impeding sand beach erosion and/or rebuilding sand beaches that is light in weight, easy and inexpensive to install, and easy to remove and relocate.